import java.util.Scanner;


public class Main1{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        double a = in.nextDouble();
        double b = in.nextDouble();
        double c = in.nextDouble();
        QuadraticSolver qs = new QuadraticSolver();
        qs.solve(a, b, c);
    }
}

/* 请在这里填写答案 */
class QuadraticSolver {
    public void solve(double a, double b, double c){
        // 在这里实现这个函数
        if(a != 0){
            if(b*b-4*a*c < 0){
                System.out.println("invalid");
            }else if(b*b-4*a*c > 0){
                double tmp = Math.sqrt(b*b-4*a*c);
                double x1 = (-b-tmp)/(2*a);
                double x2 = (-b+tmp)/(2*a);
                System.out.println("2");
                System.out.printf("%f %f",x1,x2);
            }else{
                double x = -b/(2*a);
                System.out.println("1");
                System.out.printf("%f",x);
            }
        }else{
            if(b==0){
                System.out.println("invalid");
            }else {
                System.out.println("1");
                System.out.printf("%f", -c / b);
            }
        }
    }
}
